The overall objective of this project is to use computer-controlled three-dimensional treatment of improve our ability to deliver high dose conformal therapy to patients. Five clinical sites will be studied: the brain, head and neck, lung, liver and prostate. Patients will be treated with sophisticated three dimensional conformal dose delivery on computer- controlled radiotherapy machines. Several specific kinds of information will be obtained from these clinical studies which will help determine the optimal methods for the treatment of cancer at these disease sites with conformal radiotherapy. This project will implement the use of computer-controlled conformal therapy for these sites, which will help improve the clinical utility of these conformal techniques. A major emphasis of this study is to attempt to eventually improve local control by performing dose escalation studies for treatment at four of these sites (brain, lung, liver, and prostate) to increase tumor doses beyond the standard doses which are delivered with conventional treatment plans. These escalations will be aimed at determining the maximum tolerated tumor dose which can be used, with conformal treatment techniques, at each of the sites. In addition, we will attempt to decrease normal tissue toxicity by performing treatment in head and neck cancers through the sparing of radiation dose to one parotid gland. Throughout all these clinical studies, we will attempt to better understand dose response relationships and the tolerance of normal structures to partial volume irradiation by performing dose-volume histogram analysis and then applying the results to a theoretical model predicting normal tissue complication probability (NTCP).